Deep brain stimulation (DBS) has rapidly emerged as an effective clinical treatment, such as for movement disorders, thereby revolutionizing the field of functional neurosurgery and virtually replacing tissue ablation for the treatment medically refractory movement disorders. However, little is known about the neural response, or therapeutic mechanisms of the stimulation. The subthalamic nucleus (STN) represents a target for DBS electrodes. However, the STN is a small nucleus surrounded by a variety of fiber tracts, many of which are responsible for stimulation-induced side effects.